Anodizable aluminum alloy plate and method of manufacturing the same

ABSTRACT

An anodizable aluminum plate and a method of manufacturing the anodizable aluminum plate are provided. An aluminum alloy material is provided, and the aluminum alloy material is anodized at a temperature at a voltage in a range of 4 volts (V) to 14 V.

CROSS-REFERENCE TO RELATED APPLICATIONS

This application is based on and claims priority under 35 U.S.C. § 119(a) to Korean Patent Application Serial No. 10-2017-0094094, which was filed in the Korean Intellectual Property Office on Jul. 25, 2017, the content of which is incorporated herein by reference.

BACKGROUND 1. Field

The present disclosure relates generally to the use of aluminum in exterior surfaces of electronic devices, and more particularly, to an anodizable aluminum plate and a method of manufacturing the same.

2. Description of the Related Art

Due to the development of information communication technology and semiconductor technology, the distribution and use of various electronic devices has rapidly increased. Electronic devices may perform specific functions according to programs incorporated therein.

Aluminum has been widely used as an exterior material for high-quality portable electronic devices. An aluminum alloy material is mainly composed of aluminum, and major alloying elements thereof include copper, magnesium, manganese, silicon, tin, zinc, etc.

In order to use the aluminum alloy material as an exterior material, various surface treatment methods are used. The surface treatment methods include an anodizing method in which an anode is electrically energized and a metal surface is oxidized by oxygen generated by the anode, so that an aluminum oxide film can be produced on the metal surface. When the anodizing treatment is performed on the aluminum alloy material, grains having a diameter of several nanometers in an oxide film (Al₂O₃) uniformly grow to several tens of micrometers, and the hardness of the produced oxide film is high, so that the abrasion resistance of aluminum can be improved. The surface of the anodized metal has a metal-specific texture, thereby providing a high aesthetic property. Further, an anodized metal has a corrosion-resistant surface, so that the anodized metal is excellent in corrosion resistance.

As the enlargement, thickness reduction, and portability of electronic devices have become more important, aluminum alloys having high strength are used. A design demand for a ceramic texture is also increasing. However, ceramics are poor in moldability, workability, and rigidity as an exterior material when compared with aluminum alloys. Anodized aluminum alloys implement a metallic texture, but cannot provide a soft-looking appearance that is provided by a ceramic surface.

In addition, conventional anodized aluminum alloys cannot implement a white color preferred by many consumers, and since the metal texture is not uniformly exhibited, it is difficult to apply the aluminum alloys as an exterior material for electronic devices.

SUMMARY

The present disclosure has been made to address at least the above problems and/or disadvantages and to provide at least the advantages described below. Accordingly, an aspect of the present disclosure provides an aluminum alloy plate, and a method of manufacturing the same, with a surface having a ceramic texture, which is highly demanded in design, in addition to a metal texture by anodizing an aluminum alloy according to predetermined conditions.

Another aspect of the present disclosure provides an aluminum plate, and a method of manufacturing the same, with a high-gloss white color plate without an additional coloring process.

An additional aspect of the present disclosure provides an aluminum plate, and a method of manufacturing the same, with various colors having a high-gloss ceramic texture.

A further aspect of the present disclosure provide an aluminum plate, and a method for manufacturing the same, having improved strength and being excellent in surface characteristics and mechanical characteristics through an anodizing treatment.

According to an embodiment, a method is provided for manufacturing an anodizable aluminum plate in which an aluminum alloy material is provided, and the aluminum alloy material is anodized at a temperature at a voltage in a range of 4 V to 14 V.

According to another embodiment, an anodizable aluminum plate is provided that includes an aluminum 6xxx series alloy and having a 60-degree gloss meter value of at least 120 gloss units (GU) through an anodizing treatment using a voltage in a range of 4 V to 10 V.

According to a further embodiment, an electronic device is provided that includes an exterior material made of an aluminum alloy. The electronic device includes a housing having a front cover facing a first direction and a rear cover facing a second direction opposite the first direction, and including a transparent region, which forms at least a portion of the front cover, and a display device disposed in the housing and including a screen region exposed through the front cover. The housing includes an aluminum 6xxx series alloy having a 60-degree gloss meter value of at least 120 GU through an anodizing treatment using a voltage in a range of 4 V to 10 V.

BRIEF DESCRIPTION OF THE DRAWINGS

The above and other aspects, features, and advantages of the present disclosure will be more apparent from the following detailed description when taken in conjunction with the accompanying drawings, in which:

FIG. 1 is a flowchart illustrating a method for manufacturing a plate using an aluminum alloy, according to an embodiment;

FIG. 2 is a graph illustrating a gloss unit measured using an anodizing 60-degree gloss meter for various values of voltage, using an aluminum 6xxx series alloy, according to an embodiment;

FIGS. 3A to 3C are graphs illustrating color difference meter values obtained using an aluminum 6xxx series alloy after anodizing aluminum 6xxx series alloy at various voltage values, according to an embodiment;

FIG. 4A is a diagram illustrating an enlarged schematic view of a portion of the internal structure of an aluminum plate, which has been subjected to a conventional anodizing treatment;

FIG. 4B is a diagram illustrating an enlarged schematic view of a portion of the inner structure of an aluminum plate 200, which has been subjected to an anodizing treatment, according to an embodiment;

FIG. 5A is a diagram illustrating a schematic enlarged perspective view of a portion (for a unit area S1) of the aluminum plate of FIG. 4A, which has been subjected to a conventional anodizing treatment;

FIG. 5B is a diagram illustrating a schematic enlarged perspective view of a portion (for a unit area S2) of the aluminum plate of FIG. 4B, which has been subjected to an anodizing treatment, according to an embodiment;

FIG. 6A is a diagram illustrating a cross-sectional view taken along line A-A′ of an aluminum plate, which has been subjected to a conventional anodizing treatment (excluding a coloring process) of FIG. 5A;

FIG. 6B is a diagram illustrating a cross-sectional view of the aluminum plate 300 taken along the line B-B′ in FIG. 5B, which has been subjected to an anodizing treatment (excluding a coloring process), according to an embodiment;

FIG. 7A is a diagram illustrating a cross-sectional view taken along line A-A′ of an aluminum plate 30, which has been subjected to a conventional anodizing treatment (including a coloring process) of FIG. 5A;

FIG. 7B is a diagram illustrating a cross-sectional view of the aluminum plate 300 taken along the line B-B′ in FIG. 5B, which has been subjected to an anodizing treatment (including a coloring process), according to an embodiment;

FIG. 8A is an image obtained through scanning electron microscopy (SEM) analysis by capturing an anodized film obtained by applying a voltage of 14V and then performing a Focused Ion Beam (FIB) treatment of the anodized film, according to an embodiment;,

FIG. 8B is an image obtained through SEM analysis by capturing an anodized film obtained by applying a voltage of 8V and then performing a FIB treatment of the anodized film, according to an embodiment; and

FIG. 9 is a diagram illustrating an exploded perspective view illustrating an electronic device that includes a display device configured with an aluminum alloy, according to an embodiment.

DETAILED DESCRIPTION

Embodiments of the present disclosure are described in detail with reference to the accompanying drawings. The same or similar components may be designated by the same or similar reference numerals although they are illustrated in different drawings. Detailed descriptions of constructions or processes known in the art may be omitted to avoid obscuring the subject matter of the present disclosure.

As used herein, the expressions “have”, “may have”, “include”, and “may include” refer to the existence of a corresponding feature (e.g., numeral, function, operation, or constituent element such as component), and do not exclude one or more additional features.

Herein, the expressions “A or B”, “at least one of A and B”, and “one or more of A and B” may include all possible combinations of the items listed. For example, the expressions “A or B”, “at least one of A and B”, and “at least one of A and B” refer to all of: (1) including at least one A; (2) including at least one B; and (3) including all of at least one A and at least one B.

The expressions “a first”, “a second”, “the first”, and “the second”, as used herein, may modify various components regardless of the order and/or the importance, but do not limit the corresponding components. For example, a first user device and a second user device indicate different user devices although both are user devices. For example, a first element may be referred to as a second element, and similarly, a second element may be referred to as a first element without departing from the scope of the present disclosure.

It should be understood that when an element (e.g., first element) is referred to as being (operatively or communicatively) “connected,” or “coupled,” to another element (e.g., second element), it may be directly connected or coupled to the other element or any other element (e.g., third element) may be interposed between them. In contrast, it may be understood that when an element (e.g., first element) is referred to as being “directly connected,” or “directly coupled” to another element (second element), there are no elements (e.g., third element) interposed between them.

The expression “configured to”, as used herein, may be used interchangeably with, for example, “suitable for”, “having the capacity to”, “designed to”, “adapted to”, “made to”, or “capable of”, according to the situation. The term “configured to” may not necessarily imply “specifically designed to” in hardware. Alternatively, in some situations, the expression “device configured to” may mean that the device, together with other devices or components, “is able to”. For example, the phrase “processor adapted (or configured) to perform A, B, and C” may mean a dedicated processor (e.g., embedded processor) only for performing the corresponding operations or a generic-purpose processor (e.g., central processing unit (CPU) or application processor (AP)) that can perform the corresponding operations by executing one or more software programs stored in a memory device.

The terms used herein are merely for the purpose of describing particular embodiments and are not intended to limit the scope of other embodiments. A singular expression may include a plural expression unless they are definitely different in context. Unless defined otherwise, all terms used herein, including technical and scientific terms, have the same meanings as those commonly understood by a person skilled in the art to which the present disclosure pertains. Such terms as those defined in a generally used dictionary may be interpreted to have the same meanings as the contextual meanings in the relevant field of art, and are not to be interpreted to have ideal or excessively formal meanings unless clearly defined in the present disclosure. In some cases, even terms defined in the present disclosure should not be interpreted to exclude embodiments.

An electronic device, according to various embodiments, may include at least one of, for example, a smart phone, a tablet PC, a mobile phone, a video phone, an electronic book reader (e-book reader), a desktop PC, a laptop PC, a netbook computer, a workstation, a server, a personal digital assistant (PDA), a portable multimedia player (PMP), a MPEG-1 audio layer-3 (MP3) player, a mobile medical device, a camera, and a wearable device. According to various embodiments of the present disclosure, the wearable device may include at least one of an accessory type (e.g., a watch, a ring, a bracelet, an anklet, a necklace, a glasses, a contact lens, or a head-mounted device (HMD)), a fabric or clothing integrated type (e.g., an electronic clothing), a body-mounted type (e.g., a skin pad, or tattoo), and a bio-implantable type (e.g., an implantable circuit).

According to an embodiment, the electronic device may be a home appliance. The home appliance may include at least one of, for example, a television, a digital versatile disc (DVD) player, an audio, a refrigerator, an air conditioner, a vacuum cleaner, an oven, a microwave oven, a washing machine, an air cleaner, a set-top box, a home automation control panel, a security control panel, a TV box, a game console, an electronic dictionary, an electronic key, a camcorder, and an electronic photo frame.

According to another embodiment, the electronic device may include at least one of various medical devices (e.g., various portable medical measuring devices (a blood glucose monitoring device, a heart rate monitoring device, a blood pressure measuring device, a body temperature measuring device, etc.), a magnetic resonance angiography (MRA), a magnetic resonance imaging (MRI), a computed tomography (CT) machine, and an ultrasonic machine), a navigation device, a global positioning system (GPS) receiver, an event data recorder (EDR), a flight data recorder (FDR), a vehicle infotainment device, an electronic devices for a ship (e.g., a navigation device for a ship, and a gyro-compass), avionics, security devices, an automotive head unit, a robot for home or industry, an automated teller machine (ATM) in banks, point of sales (POS) device in a shop, or an Internet of things (IoT) device (e.g., a light bulb, various sensors, electric or gas meter, a sprinkler device, a fire alarm, a thermostat, a streetlamp, a toaster, a sporting goods, a hot water tank, a heater, a boiler, etc.).

According to some embodiments, the electronic device may include at least one of a part of furniture or a building/structure, an electronic board, an electronic signature receiving device, a projector, and various kinds of measuring instruments (e.g., a water meter, an electric meter, a gas meter, and a radio wave meter). In various embodiments, the electronic device may be a combination of one or more of the aforementioned various devices. According to embodiment, the electronic device may also be a flexible device. Further, the electronic device is not limited to the aforementioned devices, and may include a new electronic device according to the development of technology.

Herein, the term “user” may indicate a person using an electronic device or a device (e.g., an artificial intelligence electronic device) using an electronic device.

FIG. 1 is a flowchart illustrating a method for manufacturing a plate using an aluminum alloy, according to an embodiment.

Referring to FIG. 1, an aluminum plate used for an exterior material or an interior material of the electronic device may be manufactured according to a process method in which an aluminum alloy material 110 is provided, in process 10; the provided aluminum alloy material 110 is polished or a surface unevenness on the provided aluminum alloy material is formed, in process 20; an aluminum plate 130 is formed by anodizing the aluminum alloy material 120 provided according to process 10, in process 30; and a surface treatment is provided on the anodized aluminum alloy, in process 40.

The aluminum alloy material 110 may be provided according to process 10. The aluminum alloy material 110 may include, for example, an alloy from a 2xxx series alloy to a high strength 7xxx series alloy, excluding pure aluminum. For example, the aluminum alloy material is mainly composed of aluminum, and major alloying elements thereof include copper, magnesium, manganese, silicon, tin, zinc, etc.

According to an embodiment, the provided aluminum alloy material 110 may be an aluminum 6xxx series alloy. The aluminum 6xxx series alloy has a medium strength level among the aluminum alloys and is excellent in corrosion resistance and weldability. Further, the aluminum 6xxx series alloy may have good cold workability through a heat treatment. In addition, some types of alloys are excellent in anodizing property and extrusion moldability.

The aluminum 6xxx series alloy used for the electronic device may be an Al—Mg—Si alloy composed of aluminum (Al), silicon (Si), and magnesium (Mg).

For example, the composition ratio of the aluminum 6xxx series alloy with respect to the total weight thereof may be 96.00 to 98.50% of aluminum (Al), 0.2 to 1.0% of silicon (Si), and 0.4 to 1.2% of magnesium (Mg), and the aluminum 6xxx series may include at least one unavoidable impurity. The at least one impurity may include at least one of iron (Fe), copper (Cu), manganese (Mn), chromium (Cr), zinc (Zn), and titanium (Ti). The impurities are contained in trace amounts. For example, copper (Cu) may be contained in the range of 0.15 to 1.1 wt %, chromium (Cr) may be contained in the range of 0.04 to 0.35 wt %, zinc (Zn) may be contained up to 0.25 wt %, and titanium (Ti) may be contained up to 0.15 wt %.

The aluminum 6xxx series alloy may be an Al 6063 alloy having a yield strength of at least 200 MPa. As another example, for the anodizing treatment, an Al—Mg—Si alloy containing 1 wt % or less of copper (Cu) may be used.

After the aluminum alloy material 110 is provided, a polishing process and/or a surface unevenness forming process may be performed on the aluminum alloy material 110, according to process 20.

The polishing process is performed so as to implement high gloss on the surface of an aluminum plate to be applied to an electronic device, and the polishing method may include a physical polishing process and/or an electrolytic polishing process.

In the polishing process, an electrolytic polishing process may be performed after the physical polishing process is performed. As another example, the physical polishing process may be performed after the electrolytic polishing process is performed. As a further example, any one of a physical polishing process and an electrolytic polishing process may be selected and performed.

A physical polishing (e.g., wheel-polishing) process may be performed by bringing a rotating polishing tool into contact with the surface of the aluminum alloy material 110. For example, the polishing tool may be constructed by mounting a member capable of causing physical friction, such as abrasive cloth, paper, leather, or polymer, on a jig, which is movable in a horizontal direction and/or a vertical direction.

The surface of the aluminum alloy material 110 seated on the jig of the polishing tool may be polished by causing the polishing cloth of the polishing tool to be rotated while pressing the polishing cloth at a predetermined constant pressure. The rotational speed and pressure of the polishing tool to be pressed against the aluminum alloy material 110 can be variously changed according to the setting of the user. In the physical polishing process, a wet polishing method in which polishing is performed in the state in which the surface of the aluminum alloy material 110 is wet and a dry polishing method in which polishing is performed in the state in which the surface of the aluminum alloy material 110 is dry may be selectively used. As another example, the wet polishing and the dry polishing may be performed in parallel.

A washing process may be included in a time period of movement between polishing processes, a time period before the polishing process, and/or a time period between multiple polishing steps. The surface gloss of the aluminum alloy material 110 can be more efficiently implemented through the washing process. For example, the polishing process may be carried out two or three times, and the washing process may be performed 3-4 times, including a process to be applied between the polishing processes or before the polishing processes. However, the number of polishing processes to be performed and the number of washing processes to be performed are not fixed, and the numbers of polishing processes and washing processes to be performed may be adjusted by the user as necessary for implementing an effective gloss on the aluminum plate.

The aluminum plate, which has been subjected to the physical polishing process, may have a value of 100 to 800 gloss unit (GU) when measured with a 60-degree gloss meter. Hereinafter, in the following examples, the contents of analysis of the gloss unit of an aluminum plate, which has been subjected to the physical polishing process, are provided.

Table 1 provides the contents of analysis of the gloss unit through a 60-degree gloss meter after the physical polishing process was performed using an aluminum 6xxx series alloy, according to an embodiment.

TABLE 1 Surface Condition Average Max Min Embodiment 1 Performing Physical 732.6 748.9 717.7 Polishing Process Embodiment 2 Performing Blasting 15.9 16.0 15.5

As shown in Table 1, the GU values are measured for Embodiments 1 and 2 after performing different processes.

In Embodiment 1, GU values are measured after physical polishing is performed on the surfaces of the provided aluminum alloy materials 110 and 120.

As a result of performing the above physical polishing process, the maximum GU value is measured as 748.9, and the minimum GU value is measured as 717.7. The average GU value is 732.6.

In Embodiment 2, GU values are measured after blasting is performed on the surfaces of provided aluminum alloy materials 110 and 120.

As a result of performing the blasting process, the maximum GU value is measured as 16.0 and the minimum GU value is measured as 15.5. The average GU value is 15.9.

From the analysis values by a surface glossmeter for the aluminum plate 130 formed after different surface processes were performed on the aluminum 6xxx series alloys of Embodiments 1 and 2, the aluminum plate 130, which was subjected to the physical polishing process, can obtain a relatively high gloss compared with the material, which was subjected to the blasting process.

An electrolytic polishing process may make the surface of the aluminum alloy material 110 smooth and/or glossy using an anodic dissolution phenomenon. For example, the electrolytic polishing process may be performed in such a manner that the aluminum alloy material 110 is accommodated in the electrolytic polishing equipment together with an electrolytic solution and protruding portions on the surface of the aluminum alloy material 110 are dissolved first.

The electrolytic polishing process may be performed while causing DC current to flow in a manufactured electrolytic solution using the aluminum alloy material 110 to be polished as an anode and using a corresponding conductor (e.g., an insoluble and electrically energizable plate) as a cathode. The electrolytic solution may be made using an acid, such as phosphoric acid or sulfuric acid, as a main component. In addition, various additives may be added in order to prevent burning of a portion in which high current flows. For example, at least one of sulphamate, a chlorine-based oxidizing agent (e.g., ammonium chloride), acetic acid, and glycerol, may be used as an additive. As another example, the polishing tool may include a filter, an air agitator, a mechanical agitator, etc. in order to remove a foreign substance generated during the process.

The electrolytic polishing process may be performed with 10 to 50 V at a temperature ranging from a room temperature to 90° C.

The surface unevenness forming process may be performed on the aluminum alloy material 110 after a polishing process (e.g., physical polishing process and/or electrolytic polishing process) may be performed on the aluminum alloy material 110. The surface unevenness forming process may be performed after the physical polishing process is performed, or may be performed after the electrolytic polishing process is performed. As another example, the surface unevenness forming process may be performed after the physical polishing process and the electrolytic process are sequentially performed, or may be performed in the state where the polishing process is not performed.

The surface unevenness forming process is performed in order to implement high gloss on the surface of the aluminum plate 130 to be applied to the electronic device, and may include a method of applying a physical force and/or a method of applying a chemical force.

The aluminum plate 110, which has been subjected to the surface unevenness forming process, may have values of 200 to 500 GU when measured with a 60-degree gloss meter.

A non-gloss anodizing process may be directly performed on the provided aluminum alloy material 110, in addition to the polishing process and/or the surface unevenness forming process.

After the polishing process and/or the surface unevenness forming process, the anodizing process may be performed on the aluminum alloy material 120 in which the polishing is performed or unevenness is formed, according to process 30. The anodizing process may be performed after the polishing process is performed, or may be performed after the surface unevenness forming process is performed. As another example, the anodizing process may be performed after the polishing process and the surface unevenness forming process are sequentially performed, or may be performed in the state in which the polishing process or the surface unevenness forming process is not be performed.

The anodizing process may include pretreatment (cleaning), anodizing, coloring, sealing, and elution processes. As another example, the anodizing process may include pretreatment (cleaning), anodizing, sealing, and elution processes performed using the metallic color of the aluminum alloy material 110.

The anodizing process may be performed by providing an apparatus configured to contain an electrolyte containing at least one or all of sulfuric acid, oxalic acid, phosphoric acid, and chromic acid, soaking the aluminum alloy materials 110 and 120 in the electrolyte solution, and providing a predetermined voltage and temperature.

The anodizing process may be performed at a temperature of about 30° C. or less and a voltage of about 10 V or less for 5 minutes or more. For example, the anodizing process may be performed at a temperature ranging from 5 to 30° C. and a voltage ranging from 4 to V for 5 to 180 minutes. The anodizing process may be performed using a voltage, which is relatively lower than that used in a general anodizing process, through which a relatively high-density film can be formed on the aluminum plate 10.

For example, referring to FIGS. 4A and 4B, compared with a case in which an anodizing treatment is performed by applying a conventional voltage (e.g., a voltage of 20 V or more (see FIG. 4A)) to the aluminum alloy material, when an anodizing treatment is performed on the aluminum alloy material at a low voltage (e.g., a voltage of 10 V or less (see FIG. 4B)), the range of the electric field per unit area, which is applied to the surfaces of the aluminum alloy materials 110 and 120, may be relatively reduced. As a result, the number of regions of unit electric field formed per unit area increases, and a film having pores with a small diameter can be formed on each of the surfaces of the aluminum alloy materials 110 and 120 in which the number of pores may be larger than the number of pores which may be formed in a film obtained by performing the conventional anodizing treatment.

The thickness of the film having many pores can be reduced compared with a film formed at a high voltage, and thus, the pore density can be increased accordingly. The surface having the high-density film may generate many irregular reflections when external light is incident on the aluminum plate, so that the reflection on the surface can be increased, a ceramic-like texture can be provided, and high gloss can be provided. The ceramic-like texture may be provided in the form of a soft texture like a foggy appearance generated on the anodized surface, for example. GU values obtained using a 60-degree gloss meter and specific values of the brightness (L), color (a), and saturation (b) obtained using a color difference meter, according to an embodiment, are described in greater detail below.

In the anodizing process, the coloring process may provide various colors to the finished aluminum plate. As another example, when the anodizing process, in which the coloring process is excluded, is performed on the aluminum plate, it is possible to provide a white color plate as a finished aluminum plate.

For example, when a coloring process is excluded from the existing anodizing process performed on an aluminum plate, it is impossible to implement white color because a metallic color inherent in aluminum appears. An anodizing process using a predetermined voltage generates films for providing a plurality of reflected light beams in the state in which no material for implementing a color tinge is added, so that a white color plate can be provided.

Hereinafter, the details of the anodizing process are described with reference to various examples.

FIG. 2 is a graph illustrating a gloss unit measured using an anodizing 60-degree gloss meter for various values of voltage, using an aluminum 6xxx series alloy, according to an embodiment of the present disclosure. The information of FIG. 2 is also shown in Table 2 below.

TABLE 2 V (voltage) Average Max Min Embodiment 1 8 V 263.3 266.4 258.4 Embodiment 2 10 V 248.0 254.6 240.5 Embodiment 3 12 V 171.7 175.2 167.0 Embodiment 4 14 V 135.7 138.5 133.5

As shown in FIG. 2 and Table 2, Embodiments 1 to 4 were tested under different conditions.

In Embodiment 1, the provided aluminum alloy materials 110 and 120 are anodized at a temperature ranging from 5 to 30° C. and at a voltage in the range of about 8 V for 5 to 180 minutes. As a result of performing the anodizing treatment, the maximum GU value is measured as 266.4, and the minimum GU value is measured as 258.4. The average GU value is 263.3.

In Embodiment 2, the provided aluminum alloy materials 110 and 120 are anodized at a temperature ranging from 5 to 30° C. and at a voltage in the range of about 10V for 5 to 180 minutes. As a result of performing the anodizing treatment, the maximum GU value is measured as 254.6, and the minimum GU value is measured as 240.5. The average GU value is 248.0.

In Embodiment 3, the provided aluminum alloy materials 110 and 120 are anodized at a temperature ranging from 5 to 30° C. and at a voltage in the range of about 12V for 5 to 180 minutes. As a result of performing the anodizing treatment, the maximum GU value is measured as 175.2, and the minimum GU value is measured as 167.0. The average GU value is 171.7.

In Embodiment 4, the provided aluminum alloy materials 110 and 120 are anodized at a temperature ranging from 5 to 30° C. and at a voltage in the range of about 14V for 5 to 180 minutes. As a result of performing the anodizing treatment, the maximum GU value is measured as 138.5, and the minimum GU value is measured as 133.5. The average GU value is 135.7.

From the gloss meter analysis values using the aluminum plate 130 obtained by anodizing an aluminum 6xxx series alloy in Embodiments 1 to 4, it is shown that as the voltage is increased, the GU values are decreased constantly. Accordingly, on the aluminum plate 130, a relatively high gloss can be obtained by using a predetermined voltage band in the anodizing treatment compared to the existing voltage (e.g., the voltage of 20 V or more).

FIGS. 3A to 3C are graphs illustrating color difference meter values obtained using an aluminum 6xxx series alloy after anodizing aluminum 6xxx series alloy at various voltage values, according to embodiments. The information of FIGS. 3A to 3C is also shown in Table 3 below. FIG. 3A shows a color difference meter value of brightness (L), FIG. 3B shows a color difference meter value of hue (a), and FIG. 3C shows a color difference meter value of the saturation (b).

TABLE 3 V (voltage) a b L Embodiment 1 8 V −0.31 1.32 86.02 Embodiment 2 10 V −0.38 2.56 85.84 Embodiment 3 12 V −0.59 3.94 84.13 Embodiment 4 14 V −0.77 5.49 82.34

As shown in FIGS. 3A to 3C and Table 3 above, color difference meter values can be found through Embodiments 1 to 4. Here, “L” indicates brightness, and “a” indicates red as the (+) value thereof increases and green as the (−) value thereof increases, and “b” indicates yellow as the (+) value thereof increases and blue as the (−) value thereof increases.

In Embodiment 1, the provided aluminum alloy materials 110 and 120 are anodized at a temperature ranging from 5 to 30° C. and at a voltage in the range of about 8 V for 5 to 180 minutes. As the result of performing the anodizing treatment, the color difference meter value of brightness (L) is 86.02. The color difference meter value of hue (a) is −0.31, and the color difference meter value of saturation (b) is 1.32.

In Embodiment 2, the provided aluminum alloy materials 110 and 120 are anodized at a temperature ranging from 5 to 30° C. and at a voltage in the range of about 10V for 5 to 180 minutes. As the result of performing the anodizing treatment, the color difference meter value of brightness (L) is 85.84. The color difference meter value of hue (a) is −0.38, and the color difference meter value of saturation (b) is 2.56.

In Embodiment 3, the provided aluminum alloy materials 110 and 120 re anodized at a temperature ranging from 5 to 30° C. and at a voltage in the range of about 12V for 5 to 180 minutes. As the result of performing the anodizing treatment, the color difference meter value of brightness (L) is 84.13. The color difference meter value of hue (a) is −0.59, and the color difference meter value of saturation (b) is 3.94.

In Embodiment 4, the provided aluminum alloy materials 110 and 120 are anodized at a temperature ranging from 5 to 30° C. and at a voltage in the range of about 14V for 5 to 180 minutes. As the result of performing the anodizing treatment, the color difference meter value of brightness (L) is 82.34. The color difference meter value of hue (a) is −0.77, and the color difference meter value of saturation (b) is 5.49.

From the gloss meter analysis values obtained using the aluminum plate 130 obtained by anodizing an aluminum 6xxx series alloy in Embodiments 1 to 4, it is shown that as the voltage is increased, a color difference meter value of brightness (L) is decreased constantly. Accordingly, on the aluminum plate 130, a white color aluminum plate can be obtained using a predetermined voltage band in the anodizing treatment compared to the existing voltage (e.g., the voltage of 20 V or more).

As another example, as the voltage is increased, the value of hue (a) is decreased and the value of saturation (b) is increased. For example, as the voltage is increased, a green tinge and a yellow tinge are increased. Accordingly, the aluminum plate has the value of hue (a) and the value of saturation (b), which are close to zero through the voltage band used for the anodizing process, an aluminum plate 130 having low saturation and a low-hue color, so that a plate having a soft ceramic texture can be manufactured.

After the anodizing process of the aluminum plate, a surface treatment process may be performed on the aluminum plate 130, according to process 40.

The surface treatment process may be performed by a coating treatment method for protecting the surface of the aluminum plate 130. For example, the surface treatment process may include an electrodeposition coating process, a coating process of a high-hardness thin film including an organic and/or inorganic hybrid resin, and a deposition process using a metal and an inert gas. The electrodeposition coating, thin film coating, and deposition processes of the surface treatment process may be sequentially performed, and some of the processes may be excluded, if necessary.

The electrodeposition coating process is a process of immersing the anodized aluminum plate 130 in an electrodeposition coating material so that the inner and outer surfaces of the anodized aluminum plate 130 can be coated with electrodeposition coating material. For example, the aluminum plate 130 may be placed in a container in which a water-soluble resin coating material is contained, and current may be supplied to the aluminum plate 130, so that a coating film can be formed on the surface thereof. The aluminum plate 130 can be coated by supplying current to a coating material solution so as to use a phenomenon in which cation particles move to a cathode and anion particles move to an anode.

According to another example, the thin film coating process is a process of coating the anodized aluminum plate 130 with, for example, a polymer material, such as epoxy, acryl, or urethane. The coated aluminum plate 130 may be subjected to a high-temperature drying process in which the aluminum plate 130 is dried at a temperature of about 80° C. or more for about one hour or more.

According to another example, the deposition process may be performed using a principle in which positive ions are caused to collide against a metal target such as titanium (Ti), silicon (Si), or chromium (Cr) using plasma due to a phenomenon in which positive ions are accelerated to a negative electrode.

The coating thickness of the aluminum plate 130, according to the surface treatment process, may be variously implemented from 1 μm to 30 μm depending on a specification.

As another example, an anodizing process may be further performed after the surface treatment process (process 40). The anodizing treatment is the same as that described above, and thus, a description thereof is omitted.

Hereinafter, the details of test processes will be described with reference to various embodiments.

FIG. 4A is a diagram illustrating an enlarged schematic view of a portion of the internal structure of an aluminum plate, which has been subjected to a conventional anodizing treatment. FIG. 4B is a diagram illustrating an enlarged schematic view of a portion of the inner structure of an aluminum plate, which has been subjected to an anodizing treatment, according to an embodiment.

FIG. 5A is a diagram illustrating a schematic enlarged perspective view of a portion (for a unit area S1) of the aluminum plate of FIG. 4A, which has been subjected to a conventional anodizing treatment. FIG. 5B is a diagram illustrating a schematic enlarged perspective view of a portion (for a unit area S2) of the aluminum plate of FIG. 4B, which has been subjected to an anodizing treatment, according to an embodiment.

Aluminum plates 200 and 300 in FIGS. 4B and 5B may be aluminum plates produced according to the aluminum plate manufacturing method of FIG. 1

Referring to FIGS. 4A, 4B, 5A, and 5B, the aluminum plates 200 and 300 may be coated with a film having a large number of pores 300 a per unit area compared with the conventional aluminum plates 20 and 30.

The anodizing process performed on the aluminum plates 200 and 300 may be conducted at a temperature of 30° C. or less and at a voltage of approximately 14 V or less for 5 minutes or more. As another example, the anodizing process may be a process in which the aluminum alloy material is treated at a temperature in the range of 5 to 30° C. and at a voltage ranging from 4 to 10 V for 5 to 180 minutes. The voltage used in the anodizing process may be lower than the voltage used in the anodizing process of a conventional aluminum alloy (e.g., 20 V or more).

The anodized aluminum plates 200 and 300 may be coated with a film including pores 300 a at a relatively higher density than that coated on the conventionally anodized aluminum plates 20 and 30. For example, in comparison with the case where anodizing is performed at a conventional voltage (e.g., the voltage of 20 V or higher), when the anodizing process is performed at a low voltage (e.g., a voltage lower than 14 V) on an aluminum 6xxx alloy material, the range of the electric field applied per unit area S2 in a region of the surface of the aluminum plate 200 or 300 may be reduced. Due to the reduction of the electric field, the size of a unit electric field region formed per unit area S2 is reduced, and the number of unit electric field regions can be increased.

In comparison with the conventional aluminum plates 20 and 30, the aluminum plates 200 and 300, according to an embodiment, may have a large number of pores 200 a and 300 a per unit area, and the size of the pores may be reduced. For example, while the number of pores 30 a formed per unit area S1 in the conventional aluminum plates 20 and 30 may be two, the number of pores 300 a formed per unit area S2 in the aluminum plates 200 and 300 may be ten. The pores 200 a and 300 a may be distributed over substantially the entire area of the aluminum plates 200 and 300 and the pores 200 a and 300 a may have a cylindrical or polygonal column shape. However, this is merely an embodiment, and pores having various shapes may be generated according to the conditions of the anodizing process, and a design for the size and the number of pores may be changed.

Since the aluminum plates 200 and 300 include a large number of pores 200 a and 300 a per unit area S2 in comparison with the conventional aluminum plates 20 and 30, the size of each of the pores in the aluminum plates 200 and 300 may be small. For example, the inner diameters 300 b of the plurality of pores 200 a and 300 a included in the anodized aluminum plates 200 and 300 may be relatively smaller than the inner diameters 30 b of the pores 20 a 30 and 30 a of the conventionally anodized aluminum plates 20 and 30.

Since the aluminum plates 200 and 300 include a large number of pores 200 a and 300 a per unit area in comparison with conventional aluminum plates 20 and 30, the interval 300 c between the pores may be relatively small. For example, the interval 300 c between the plurality of pores 200 a and 300 a included in the anodized aluminum plates 200 and 300 may be relatively smaller than the interval 30 c between the pores 20 a and 30 a of the conventionally anodized aluminum plates 20 and 30. The surface region, which forms the interval 300 c between the pores, may form the outer surfaces of the aluminum plates 200 and 300 together with the pores 200 a and 300 a and may be a region in which practically external light is directly reflected.

FIG. 6A is a diagram illustrating a cross-sectional view taken along line A-A′ of an aluminum plate, which has been subjected to a conventional anodizing treatment (excluding a coloring process) of FIG. 5A. FIG. 6B is a diagram illustrating a cross-sectional view of the aluminum plate 300 taken along the line B-B′ in FIG. 5B, which has been subjected to an anodizing treatment (excluding a coloring process), according to an embodiment.

FIG. 7A is a diagram illustrating a cross-sectional view taken along line A-A′ of an aluminum plate, which has been subjected to a conventional anodizing treatment (including a coloring process) of FIG. 5A. FIG. 7B is a diagram illustrating a cross-sectional view of the aluminum plate taken along the line B-B′ in FIG. 5B, which has been subjected to an anodizing treatment (including a coloring process), according to an embodiment.

Aluminum plates 400 and 500 in FIGS. 6B and 7B may be aluminum plates produced according to the aluminum plate manufacturing method of FIG. 1.

Referring to FIGS. 6A and 6B, the aluminum plate 400 may be coated with a film having a large number of pores 400 a per unit area in comparison with the conventional aluminum plate 40. As another example, due to the large number of pores 400 a per unit area, the aluminum plate 400 may be manufactured such that the interval 400 c between the pores 400 a is narrower in comparison with those in the conventional aluminum plate 40. As a result, the effect of causing irregular reflection due to external light can be increased. For example, in the conventional structure, pores 40 a may be arranged at an interval 40 c in the surface region where irregular reflection occurs. In the structure according to an embodiment, since a large number of pores 400 a having a relatively small inner diameter 400 b may be arranged, the interval 400 c of the pores 400 a in the surface region 400 d may be smaller than the interval 40 c in the conventional aluminum plate 40 c. Accordingly, the regions where light is reflected may occur relatively densely, and irregular reflection of light may at a closer interval than that in the conventional structure.

The aluminum plates 40 and 400 of FIGS. 6A and 6B are aluminum plates 40 and 400 manufactured through a pretreatment (cleaning), anodizing, sealing, and elution processes during the anodizing treatment. Since the coloring process is excluded from the anodizing treatment, an aluminum plate having a color arbitrarily added in addition to the metallic color of the metal itself may be excluded.

The non-colored aluminum plate 400 may include a large number of reflective portions 400 d while having a relatively small thickness 400 c in comparison with a conventional non-colored aluminum plate 40. Respective reflective portions 400 d may extend with respect to each other, and may form the outer surface of the non-colored aluminum plate 400. According to an embodiment, the reflective portions 400 d are regions where irregular reflection occurs due to light transmitted from the outside, and may variously exhibit the gloss of the aluminum plate and the feeling of texture imparted to the user.

Since a coloring chemical is relatively hardly infiltrated into the pores 400 a in the non-colored aluminum plate 400 in comparison with the colored aluminum plate 500 to described later (the colored aluminum plate 500 of FIG. 7), light-absorbing portions are decreased, so that the reflected light can be further increased.

The non-colored aluminum plate 400 may provide a white color surface. For example, unlike conventional uncolored aluminum plate 40, in which the metallic color of the metal itself (e.g., silver or gray) is implemented, the non-colored aluminum plate 400 may cause countless irregular reflections through the increased pore density and the reflective portions 400 d, thereby providing a white color surface. The surface, which provides the white color, may provide an external appearance, which has an evenly soft texture like a foggy appearance (e.g., an external appearance of a pastel white tone, as described above) due to the large number of irregular reflections.

Referring to FIGS. 7A and 7B, the aluminum plate 500 may be coated with a film having a large number of pores 500 a per unit area in comparison with the conventional aluminum plate 50. The aluminum plates 50 and 500 of FIGS. 7A and 7B are aluminum plates 50 and 500 manufactured through a pretreatment (cleaning), anodizing, coloring, sealing, and elution processes during the anodizing treatment. Through the coloring process in the anodizing treatment, an aluminum plate having a color arbitrarily added in addition to the metallic color of the metal itself may be manufactured.

The colored aluminum plate 500 may include a large number of reflective portions 500 d while having a relatively small thickness 500 c in comparison with a conventional colored aluminum plate 50. Respective reflective portions 500 d may extend with respect to each other, and may form the outer surface of the colored aluminum plate 500. The reflective portions 500 d are regions where irregular reflection occurs due to light transmitted from the outside, and may variously exhibit the gloss of the aluminum plate and the feeling of texture imparted to the user.

Since a coloring chemical 500 e is relatively easily infiltrated into pores 500 a in the colored aluminum plate 500 in comparison with the non-colored aluminum plate 400, it is possible to provide a variously colored surface having a pastel-tone texture and gloss as described above.

FIG. 8A is an image obtained through SEM analysis by capturing an anodized film obtained by applying a voltage of 14V and then performing a FIB treatment of the anodized film, according to an embodiment. FIG. 8B is an image obtained by through SEM analysis capturing an anodized film obtained by applying a voltage of 8V and then performing a FIB treatment of the anodized film, according to an embodiment.

Referring to FIGS. 8A and 8B, the size of a plurality of pores and intervals between the plurality of pores (e.g., walls) in an aluminum plate, which has been subjected to an anodizing treatment by applying a voltage of 14 V, and the size of a plurality of pores and intervals between the plurality of pores an aluminum plate, which has been subjected to an anodizing treatment using a voltage of 8 V, are compared with each other.

When comparing sizes of the plurality of pores and the walls in FIGS. 8A and 8B, the size including one pore and walls thereof in the case of FIG. 8A is 0.45 to 1.1 μm, while the size including one pore and the walls thereof in the case of FIG. 8B is 0.3 to 0.55 μm.

According to the results of analysis, compared with the case where the anodizing treatment is performed at a conventional voltage, when the anodizing treatment is performed on an aluminum 6xxx series alloy material at a relatively low voltage, the range of the electric field applied per unit area in a region of the surface of the aluminum plate may be reduced. Accordingly, in comparison with the size of the inner diameter of pores in the conventional anodized aluminum plate, the pores in the aluminum plate, which was subjected to the anodizing treatment at a relatively low voltage, may have a relatively small inner diameter.

FIG. 9 is a diagram illustrating an exploded perspective view of an electronic device that includes a display device configured with an aluminum alloy, according to an embodiment.

Referring to FIG. 9, an electronic device 600 includes a housing 610 having a front cover 611 facing a first direction (−Y) and a rear cover 612 facing a second direction (+Y) opposite the first direction of the front cover 611. The housing 610 may include a transparent region that forms at least a portion of the front cover. The electronic device 600 includes a display device 620 that is disposed within the housing 610 and includes a screen region exposed through the front cover 611. The housing 610 may be made of an aluminum alloy capable of being anodized, and the aluminum alloy may be configured as an exterior material or an interior material including the above-mentioned aluminum 6xxx series alloy.

The housing 610 is configured to accommodate various electronic components and the like, and at least a portion of the housing 110 may be made of a conductive material. For example, the housing 610 may include sidewalls forming the outer surface of the electronic device 600. Alternatively, a portion of the housing 610, which is exposed as the exterior of the electronic device 600, may include a conductive material. Within the housing 610, a printed circuit board 650 and/or a battery 660 may be accommodated. For example, a processor, a communication module, various interfaces, a power management module, or a control circuit may be configured in the form of an integrated circuit chip, and may be mounted on the printed circuit board 650. For example, the control circuit may be a portion of the above-described processor or communication module.

The display device 620 may be at least partially made of a material that transmits radio waves or magnetic fields. For example, the display device 620 may include a window member made of a tempered glass material and a display panel mounted on the inner surface of the window member. A touch panel may be mounted between the window member and the display device. For example, the display device 620 may be an output device for outputting a screen, and may be used as an input device equipped with a touch screen function.

As described above and according to an embodiment, a method for manufacturing an anodizable aluminum plate includes a process of providing an aluminum alloy material, and a process of performing an anodizing treatment on the provided alloy material at a temperature in a range of 5 to 30° C. and at a voltage of 4 to 14 V for 5 to 180 minutes.

The anodizing process may include anodizing the provided alloy material at a temperature in a range of 5 to 30° C. and at a voltage of 4 V to 10 V for 5 to 180 minutes.

The process of performing the anodizing treatment may include a pretreatment process, an anodizing process, a sealing process, and an elution process.

The process of performing the anodizing treatment may include a pretreatment process, an anodizing process, a coloring process, a sealing process, and an elution process.

After the process of providing the aluminum alloy material, the method may further include a process of polishing the provided alloy material or a process of forming surface unevenness.

The process of polishing the aluminum alloy material may include a physical polishing process of wet- or dry-polishing the surface of the aluminum alloy material, and the aluminum plate, which have been subjected to the physical polishing process, may have a 60-degree gloss meter value of 100 to 800 GU.

The process of polishing the aluminum alloy material may include an electrolytic polishing step of polishing the aluminum material at a temperature ranging from a room temperature to 90° C. and at a voltage of 10 to 50 V.

The aluminum alloy material on which the electrolytic polishing process has been performed may have a 60-degree gloss meter value of 200 to 500 GU.

The anodized aluminum plate includes a plurality of pores, the length of the cross-section of a structure including at least one pore and the walls surrounding the pore is from 0.30 to 0.55 μm, and a 60-degree gloss meter value of the anodized aluminum plate may be 200 GU or more.

The anodized aluminum plate may have a color difference meter value of brightness (L) of 85.00 or more.

The anodized aluminum plate may have a color difference meter value of hue (a) of −0.40 or more and a color difference meter value of saturation (b) of 3.00 or less.

A surface treatment process for protecting the anodized surface by performing coating on the surface of the anodized plate may be further included after the process of performing the anodizing treatment on the aluminum alloy material.

The surface treatment process may include at least one of electrophoretic coating, a process of coating a high-hardness thin film including an organic and/or inorganic hybrid resin, and a deposition process using a metal and an inert gas.

According to an embodiment, an anodizable aluminum plate may have a 60-degree gloss meter value of at least 120 GU through the anodizing treatment using a voltage of 4 V to 10 V.

The anodized aluminum plate may include a plurality of pores, and the length of a cross-section of a structure including at least one pore and walls surrounding the pore may be 0.30 to 0.55 μm.

A 60-degree gloss meter value of the anodized aluminum plate may be 200 GU or more.

The aluminum plate may include a white color which has a color difference meter value of brightness (L) of 85.00 or more.

The aluminum plate may include a white color which has a color difference meter value of hue (a) of −0.40 or more.

The aluminum plate may include a white color which has a color difference meter value of saturation (b) of 3.00 or less.

The aluminum plate includes an aluminum 6xxx series alloy, and the aluminum 6xxx series alloy may include 0.2-1.0 wt % of silicon (Si), 0.4-1.2 wt % of magnesium (Mg), and a balance including aluminum (Al) and at least one inevitable impurity.

The at least one impurity of the aluminum 6xxx series alloy may be at least one of iron (Fe), copper (Cu), manganese (Mn), chromium (Cr), zinc (Zn), and titanium (Ti).

According to an embodiment, an electronic device is provided including an exterior material made of an aluminum alloy. The electronic device may include a housing including a front cover facing a first direction and a rear cover facing a second direction opposite the first direction, and including a transparent region, which forms at least a portion of the front cover, and a display device disposed in the housing and including a screen region exposed through the front cover. The housing may include an aluminum 6xxx series alloy, and may have a 60-degree gloss meter value of at least 120 GU through an anodizing treatment using a voltage of 4 V to 10 V.

According to an embodiment, it is possible to implement a surface having a ceramic texture, which is highly demanded in design, in addition to a metal texture by anodizing an aluminum alloy. Thus, it is possible to provide a plate, which has a beautiful appearance.

According to an embodiment, it is possible to provide a high-gloss white color plate through a simple process in which an additional coloring process is not performed.

According to an embodiment, it is possible to implement a plate having various colors and a high-gloss ceramic texture.

According to an embodiment, it is possible to provide a plate having a soft pastel-tone by manufacturing, through an anodizing treatment, where the plate has a surface with countless irregular reflections.

While the present disclosure has been shown and described with reference to certain embodiments thereof, it will be understood by those skilled in the art that various changes in form and detail may be made therein without departing from the spirit and scope of the disclosure as defined by the appended claims. 

What is claimed is:
 1. A method of manufacturing an anodizable aluminum plate, the method comprising: providing an aluminum alloy material; and anodizing the aluminum alloy material at a voltage in a range of 4 volts (V) to 14 V.
 2. The method of claim 1, wherein anodizing the aluminum alloy material comprises anodizing the alloy material at a temperature in a range of 5° C. to 30° C. and at voltage in a range of 4 V to 10 V for 5 to 180 minutes.
 3. The method of claim 2, wherein anodizing the aluminum alloy material comprises a pretreatment process, an anodizing process, a sealing process, and an elution process.
 4. The method of claim 3, wherein anodizing the aluminum alloy material further comprises a coloring process.
 5. The method of claim 3, further comprising: polishing the aluminum alloy material or forming surface unevenness after providing the aluminum alloy material.
 6. The method of claim 5, wherein polishing the aluminum alloy material comprises a physical polishing process of wet or dry polishing of a surface of the aluminum alloy material, and wherein a 60-degree gloss meter value of the anodizable aluminum plate on which the physical polishing process has been performed is 100 to 800 GU.
 7. The method of claim 5, wherein polishing the aluminum alloy material comprises an electrolytic polishing process in which the aluminum alloy material is polished at a temperature ranging from a room temperature to 90° C. and a voltage in a range of 10 V to 50 V.
 8. The method of claim 7, wherein the 60-degree gloss meter value of the anodizable aluminum plate on which the electrolytic polishing process has been performed is 200 to 500 gloss units (GU).
 9. The method of claim 2, wherein: the anodized aluminum plate includes a plurality of pores, and a length of a cross-section of a structure including at least one pore and walls surrounding the pore is in a range of 0.30 micrometers (μm) to 0.55 μm, and the 60-degree gloss meter value of the anodized aluminum plate is 200 GU or more.
 10. The method of claim 2, wherein the anodized aluminum plate has a color difference meter value of brightness (L) of 85.00 or more.
 11. The method of claim 10, wherein the anodized aluminum plate has the color difference meter value of hue (a) of −0.40 or more and the color difference meter value of saturation (b) of 3.00 or less.
 12. The method of claim 2, further comprising: protecting an anodized surface by performing coating on a surface of the anodized aluminum plate after the anodizing of the aluminum alloy material.
 13. The method of claim 12, wherein protecting the anodized surface comprises at least one of electrophoretic coating, a process of coating a high-hardness thin film including an organic and/or inorganic hybrid resin, and a deposition process using a metal and an inert gas.
 14. An anodizable aluminum plate, wherein the anodizable aluminum plate has a 60-degree gloss meter value of at least 120 gloss units (GU) through an anodizing treatment using a voltage in a range of 4 volts (V) to 10 V.
 15. The anodizable aluminum plate of claim 14, wherein the anodized aluminum plate includes a plurality of pores, and a length of a cross section of a structure including at least one pore and a wall surrounding the pore is in a range of 0.30 micrometers (μm) to 0.55 μm.
 16. The anodizable aluminum plate of claim 14, wherein the anodizable aluminum plate includes a white color, which has a color difference meter value of brightness (L) of 85.00 or more.
 17. The anodizable aluminum plate of claim 16, wherein the anodizable aluminum plate includes the white color which has a numerical color difference meter value of hue (a) of −0.40 or more and a color difference meter value of saturation (b) of 3.00 or less.
 18. The anodizable aluminum plate of claim 14, wherein the anodizable aluminum plate comprises an aluminum 6xxx series alloy, which contains 0.2-1.0 wt % of silicon (Si), 0.4-1.2 wt % of magnesium (Mg), and a remainder includes aluminum (Al) and at least one impurity.
 19. The anodizable aluminum plate of claim 18, wherein the at least one impurity of the aluminum 6xxx series alloy is at least one of iron (Fe), copper (Cu), manganese (Mn), chromium (Cr), zinc (Zn), and titanium (Ti).
 20. An electronic device including an exterior material made of an aluminum alloy, the electronic device comprising: a housing comprising a front cover facing a first direction and a rear cover facing a second direction opposite the first direction, and including a transparent region, which forms at least a portion of the front cover; and a display device disposed in the housing and having a screen region exposed through the front cover, wherein the housing includes an aluminum 6xxx series alloy, and has a 60-degree gloss meter value of at least 120 gloss units (GU) through an anodizing treatment using a voltage in a range of 4 volts (V) to 10 V. 